Variables

Is there a difference between declaring all the variables in the first scene or declaring the variables in each scene?

Because I think declaring them in the first scene is more orderly and causes me less confusion.

it depends on your needs, if you need a variable that accumulates values, like score, you declare the variable in the first scene, but if you have a variable that needs to be reset in each scene, you declare it in each scene, like a variable that make more objects be generated